SOLUTION: Hi! Please Help! How do I turn this into an algebra problem??? Two copy machines are available to print documents. The newer copy machine can do my set of documents in 15 min

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Question 83262: Hi! Please Help!
How do I turn this into an algebra problem???
Two copy machines are available to print documents. The newer copy machine can do my set of documents in 15 minutes. If both machines print at the same time, they can do this set of documents in 12 minutes. How long would it take the older copy machine to do my documents?
Thank you.
Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website!

Let x=amount of time for the older machine to do the job
New machine can do (1/15) of the job per minute
The old machine can do (1/x) of the job per minute
Working together they can do (1/15)+(1/x) of the job per minute and we are told that this equals (1/12). So our equation to solve is:
(1/15)+(1/x)=(1/12) multiply each term by 60x to get rid of fractions
4x+60=5x subtract 4x from both sides
4x-4x+60=5x-4x collect like terms
x=60 minutes-----------------amount of time for the older machine to do the job
CK
(1/15)+(1/60)=(1/12)
(4/60)+(1/60)=5/60
5/60=5/60
Hope this helps----ptaylor